selftests: fchmodat2: remove duplicate unneeded defines

These duplicate defines should automatically be picked up from kernel
headers. Use KHDR_INCLUDES to add kernel header files.
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Message-Id: <20230805073809.1753462-4-usama.anjum@collabora.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

tools/testing/selftests/fchmodat2/Makefile

 # SPDX-License-Identifier: GPL-2.0-or-later
 
-CFLAGS += -Wall -O2 -g -fsanitize=address -fsanitize=undefined
+CFLAGS += -Wall -O2 -g -fsanitize=address -fsanitize=undefined $(KHDR_INCLUDES)
 TEST_GEN_PROGS := fchmodat2_test
 
 include ../lib.mk

tools/testing/selftests/fchmodat2/fchmodat2_test.c

@@ -9,26 +9,6 @@
 
 #include "../kselftest.h"
 
-#ifndef __NR_fchmodat2
-	#if defined __alpha__
-		#define __NR_fchmodat2 562
-	#elif defined _MIPS_SIM
-		#if _MIPS_SIM == _MIPS_SIM_ABI32	/* o32 */
-			#define __NR_fchmodat2 (452 + 4000)
-		#endif
-		#if _MIPS_SIM == _MIPS_SIM_NABI32	/* n32 */
-			#define __NR_fchmodat2 (452 + 6000)
-		#endif
-		#if _MIPS_SIM == _MIPS_SIM_ABI64	/* n64 */
-			#define __NR_fchmodat2 (452 + 5000)
-		#endif
-	#elif defined __ia64__
-		#define __NR_fchmodat2 (452 + 1024)
-	#else
-		#define __NR_fchmodat2 452
-	#endif
-#endif
-
 int sys_fchmodat2(int dfd, const char *filename, mode_t mode, int flags)
 {
 	int ret = syscall(__NR_fchmodat2, dfd, filename, mode, flags);